This invention concerns the introduction of fluids into a system without microcontaminants entering the fluid flow. More particularly, the invention relates to a fluid dispensing and metering unit which can be combined with other similar units to create a flow control manifold. The flow control manifold provides for the addition of a variety of different fluids into a single, clean continuous duct.
In the course of manufacturing wafers for integrated circuits, the wafers are rinsed with various chemicals and deionized water for coating, etching and cleaning processes. It is of the utmost importance that these fluids are applied to the wafers in a very clean state, absent contaminants that may reside in the fluid conducting system. Possible contaminants include residual fluids that previously passed through the system and microscopic particles of grease, dust and metallic particles generated from individual pieces of the fluid conducting system rubbing against each other. If such contaminants are inadvertently sprayed onto the wafers, the potential utilization of the wafer for the construction of an integrated circuit may be significantly decreased. For example, the presence of residual fluids could chemically effect subsequent processing steps of the wafer.
To prevent even microscopic particles from entering the fluid flow, thorough rinsing of the fluid delivery system must be performed between processing steps. The optimum means for conducting such a thorough rinsing would have a minimum surface area and would eliminate areas in which particle accumulation is likely. For example, previous fluid delivery systems have included threaded connection surfaces. The hollow between each individual thread can hold minute amounts of contaminants. Complete rinsing of each hollow is a very difficult task. Other prior assemblies have used numerous strands of tubing to deliver each particular fluid into the delivery system. Such a system generally has more joints and surfaces for contaminants to reside, making flushing of the system less thorough and more time consuming.